Cardiac insufficiency is one of the most prevalent internal-medicine diseases in the developed countries of this world. An increased frequency of cardiac insufficiency is observed with increasing age.
In general, cardiac insufficiency is understood as the inability of the heart to supply the organism with sufficient blood circulation. It should also be noted that reduced blood circulation (also referred to as reduced cardiac output) results in an insufficient supply of oxygen and/or nutrients to the tissue. This can manifest itself symptomatically in reduced physical capacity and/or increased shortness of breath (so-called dyspnea), as well as increased water retention (e.g., edema in the legs). The causes of this will not be addressed further here.
Furthermore, it should be noted that cardiac insufficiency is also frequently associated with a dilated left ventricle with reduced pumping function.
Since populations are becoming increasingly older, an increasing number of sick people can also be expected. This means an increasing need for treatment.
Previous approaches to treatment are oriented towards the respective stage of the disease.
In the so-called mild and moderate stages (New York Heart Association NYHA I-II), treatment is generally administered in the form of medication. In addition, there is the possibility of implanting a defibrillator (implantable cardioverter-defibrillator (ICD)) or cardiac resynchronization therapy (CRT).
In the advanced and terminal stages (New York Heart Association NYHA III-IV), a heart transplantation must be considered in some circumstances. Alternatively, particularly in elderly patients, the use of a left ventricular assist device (LVAD) is also indicated. Since the number of donor organs is limited, the use of a left ventricular assist device can also be used as an interim measure.
Previous LVAD systems consisted of contacting/pulsing units which due to their size, for example were arranged partially outside of the body. Newer LVAD systems are generally placed intracorporeally and have a continuous flow. A delivery rate of up to 8 liters per minute can be made available with the newer systems, thus enabling the entire cardiac output to be replaced.
However, the various newer LVAD systems are nonetheless disadvantageous for a wide variety of reasons that will be outlined below.
One thing that all of these systems have in common is that they must be implanted by means of an operation. As a rule, this entails opening up the thorax, and the support of a cardiopulmonary machine is often required. In other words, a costly and risk intervention under general anesthesia is necessary. What is more, all of these newer systems have an external power unit and/or an external control unit. The connection of the external systems is critical, since the danger exists of germs penetrating along the wired connection. Furthermore, the previous newer systems are designed for continuous support, so a high level of blood flow is maintained even in periods in which there is no elevated need, such as during resting periods. This generally has a negative impact on the size of the required power supply unit and thus poses an obstacle to the shift to an intracorporeal design. Moreover, use of the previous systems in patients with peripheral occlusive arterial disease (POAD) and so-called porcelain aorta (calcified aorta) is very restricted.